An opening Three-Bid, called a preempt, shows a weak hand can take five or more tricks if your suit is trumps, but is unlikely to take any tricks in any other suits. To open (or overcall) a Three-Bid, you should have:
No 4-card major (especially if partner is not yet a passed hand).
Always consider the vulnerability. If you're vulnerable (your side has made a game), the penalties for not making your contract are much higher. Open a vulnerable Three-Bid only if you have strong 7-card suit. Here are some example hands:
973 3 KQJ942 Q43 -- Open 3D (but pass if you're vulnerable).
AKJ10743 5 8654 8 -- Open 3S at any vulnerability.
A6 J943 Void KJ86432 -- Pass. You have too much strength outside your suit to open 3C, which would make it almost impossible to find a heart fit if you have one. This hand may be easier to describe later (with an overcall, or a response to partner's opening bid).
AKJ10763 82 QJ54 Void -- Open 4S. This has too much playing strength for 3S.
K84 AK108654 86 4 -- Open 1H. This hand is too strong for a 3-bid.
Once you make a Three-Bid, you've described your entire hand, so you shouldn't bid again unless partner makes a forcing bid. The only ways partner can force are by bidding a new suit, by cuebidding the opponent's suit, or by asking for aces.
If partner opens a Three-Bid, it's up to you to place the contract. With a weak hand and no fit, you pass. With a stronger hand, don't count just points -- what's important is the number of tricks you can take. Consider the vulnerability and try to visualize partner's hand, then count your potential tricks.
A bid of game in partner's suit or notrump (3H-4H or 3D-3NT) shows a strong playing hand with a fit and quick tricks (aces and kings).
A new suit response (3C-3S) shows a strong hand and a good, usually 6+-card suit. Partner won't have 4-card support (even 3-card support is unlikely), so don't suggest a new suit unless you have a very good one.
A simple raise below game (3C-4C) shows a trump fit, but no interest in game. You may raise to put pressure on the opponents, to compete for the contract or to sacrifice. A raise does not invite partner to bid again.
A Three-Bid can be valuable when you want to "steal" the hand with a sacrifice. If the opponents bid game, you bid higher in partner's suit, hoping to get a smaller minus score than if the opponents had made game.
For a sacrifice to be profitable, your hand must be weak enough in high cards for you to be sure the opponents can make a game. Your hand must also be strong enough in playing tricks and trump support for you to be sure you won't be set more than two (sometimes three) tricks.
The best time for a sacrifice is when you are not vulnerable and the opponents are-when their game would give them a 700-pt. rubber. You can then afford to be doubled and go down as many as three tricks (losing 500 pts.) for your sacrifice to be profitable.
You are not vulnerable. Partner opens 3S and the opponent on your right passes. What is your bid?
4S. Your spade support will help partner take at least 5 (or as many as 7) trump tricks, plus your three top tricks in the minor suits. It's also likely that he can score one or two more tricks by trumping hearts in your hand or setting up your diamonds.
Pass. This hand has more points than the previous example, but much less playing strength. You know partner has no outside aces or kings, so you may have at least three side-suit losers (or perhaps five!), as well as a possible spade loser or two.
3NT. Partner is vulnerable, so he should have a good 7-card suit (you have the ace, so he must have at least the KQ). You can therefore count 9 tricks -- 7 clubs and 2 aces -- and you have a "stopper" in diamonds if the opponents lead that suit.
© Karen Walker